﻿using System;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("请输入圆的半径：");
            double a = double.Parse(Console.ReadLine());
            double cir = 2 * a * 3.14;
            double area = a * a * 3.14;
            cir = (double)Math.Round((double)cir, 2);
            area = (double)Math.Round((double)area, 2);
            Console.Write("面积{1}", cir, area);

        }





    }
}
